There has been conventionally provided a sensor including a microchannel through which a solution flows, and having a working electrode for subjecting a substance in the solution to electrochemical measurement, the working electrode being formed in a planar shape on the bottom surface of the channel (for example, Patent Document 1).
In addition, Patent Document 2 describes a biosensor including, on an upstream side of a planar working electrode, a minute protrusion for removing an interfering substance in a biological sample, the minute protrusion having a surface modified with a conductive material. Patent Document 2 described above also describes that simultaneous measurement for two components can be achieved with the working electrode and the minute protrusion as electrodes. In addition, Patent Document 3 describes a biosensor including, on the upstream side of a planar working electrode, a minute protrusion formed of a thermoplastic resin.    Patent Document 1: JP 2000-9679 A    Patent Document 2: JP 2000-97899 A    Patent Document 3: JP 2006-201080 A